The invention is based on a check valve, as described in U.S. Pat. No. 3,725,990, for instance. In such a check valve, a valve element, which is typically embodied as a ball, is pressed against a valve seat by means of a valve spring, which is generally embodied as a helical spring, and often as a conical helical spring; the valve seat is provided in a valve housing in order to close a valve opening surrounded by the valve seat as long as a pressure of a pressure fluid acting upon the valve body via the valve opening is inadequate to lift the valve element from the valve seat counter to the engaging spring force. Accordingly, at a pressure more or less accurately defined by the spring force selected, a check valve opens at the valve opening, which at lesser pressures, and independently of the level of the pressure whenever the pressure fluid acts on the opposite side of the valve element from the valve opening, it blocks this valve opening. Depending on the intended use, or as a function of the adjoining components of a hydraulic or pneumatic system, the valve housing may take various forms; the valve housing of U.S. Pat. No. 3,725,990 mentioned above is used to make so-called insert check valves, which are inserted directly into a pressure fluid conduit or line, and are relatively simple in design and can be embodied by a cuplike sheet-metal housing, for instance, which is flanged inward on its end remote from the valve seat in order to form a support surface for the end of the spring remote from the valve element, or for a plate or the like supporting this end of the spring.
For a flow regulating valve, which is moreover intended as an insert valve and in addition to the usual components of a check valve includes an actuating device with whose aid a ball-like valve element can be lifted in a defined way from the valve seat regardless of the height and orientation of the pressure fluid pressure, it is also known from German Offenlegungsschrift 24 23 643 to embody the valve housing as a relatively heavy and bulky die-cast housing or the like, and to use a housing in the form of a cuplike cage as a support for the compression spring acting upon the valve element; the pressure spring can be supported on the bottom of the cage, and its open end is press-fitted form-fittingly into an annular groove of the valve housing, causing permanent deformation of the cage material.
In the known check valves of the type described above, which by the use of an additional actuating device can optionally be used as flow regulating valves, it has proved to be a problem that when the valve parts are assembled to make a functional valve, at least one component of the valve must be permanently deformed--in the case of the valve of U.S. Pat. No. 3,725,990, this is the edge on the open side of the cup-like valve housing, while in the valve of German Offenlegungsschrift 24 23 643, it is the open end of the cuplike cage serving as a support for the compression spring. The consequence is that the production of the individual parts of the valve, on the one hand, and the assembly of the finished valve on the other cannot be separated from one another either in terms of space or time, and in the final analysis the deformation steps and deforming tools determine the rate and precision of the assembly. Moreover, final quality control cannot be done until after the final assembly or final completion of the known valves.